Energy storage and delivery for power trains of work vehicles

ABSTRACT

A power train arrangement for a work vehicle with an engine may include an infinitely variable power source (“IVP”). An energy storage device may be configured to receive energy from the IVP for storage and to provide stored energy from the energy storage device to power one or more components of the IVP. A transmission may be configured to relay power from the engine and from the one or more components of the IVP to other components of the vehicle. A transient power event may be identified, during which a present operating state of the engine does not provide sufficient power for operations of the work vehicle. The energy storage device may be caused to provide stored energy to power the one or more components of the IVP source and thereby to provide power to the transmission.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a continuation-in-part of U.S. application Ser. No. 14/145,599, filed on Dec. 31, 2013.

STATEMENT OF FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT

Not applicable.

FIELD OF THE DISCLOSURE

This disclosure relates to vehicle transmissions and vehicle power management, including infinitely variable transmissions and energy storage systems.

BACKGROUND OF THE DISCLOSURE

It may be useful, in a variety of settings, to utilize both a traditional engine (e.g., an internal combustion engine) and an infinitely variable power source (e.g., an electric or hydrostatic motor, a variable chain drive, and so on) to provide useful power. For example, a portion of engine power may be diverted to drive a first infinitely variable machine (e.g., a first electric machine acting as a generator), which may in turn drive a second infinitely variable machine (e.g., a second electric machine acting as a motor using electrical power from the first electrical machine). In certain configurations, power from both types of sources (i.e., an engine and an infinitely variable power source) may be combined for final power delivery (e.g., to a vehicle axle) via an infinitely variable transmission (“IVT”) or continuously variable transmission (“CVT”). This may be referred to as “split-mode” or “split-path mode” operation because power transmission may be split between the mechanical path from the engine and the infinitely variable path. Split-mode operation may be attained in various known ways. For example, a planetary gear set may be utilized to sum rotational power from an engine and from an electric machine, with the summed power transmitted downstream within an associated power train. This may allow for delivery of power (e.g., to vehicle wheels) with an infinitely variable effective gear ratio. Various issues may arise, however, including limitations relating to the maximum practical speed of variable power sources.

The operation of other types of transmissions, as well as IVT or CVT transmissions, may introduce various other issues. For example, in certain configurations, transmission shifts (e.g., transitions between different gear ratios) may result in jolts to a vehicle, lags or other transient effects on available power (e.g., at the wheels of a vehicle or at an attached tool or implement), or other detrimental effects on system performance and user experience.

SUMMARY OF THE DISCLOSURE

According to one aspect of the disclosure, a power train arrangement for a work vehicle with an engine may include an infinitely variable power source (“IVP”). An energy storage device may be configured to receive energy from the IVP for storage and to provide stored energy from the energy storage device to power one or more components of the IVP. A transmission may be configured to relay power from the engine and from the one or more components of the IVP to other components of the vehicle. A transient power event may be identified, during which a present operating state of the engine does not provide sufficient power for operations of the work vehicle. The energy storage device may be caused to provide stored energy to power the one or more components of the IVP and thereby to provide power to the transmission.

In certain embodiments, during the transient power event, the transmission may also receive power from the engine, such that the operations of the work vehicle may be executed using, at least in part, power from the engine and stored energy from the energy storage device. The transient power event may include a shift operation, operation of a tool of the work vehicle, or an operation of the vehicle while the vehicle engine is shut off.

In certain embodiments, infinitely variable transmissions of various configurations may be configured to receive power from the one or more components of the IVP, An infinitely variable transmission may include, for example, one or more planetary or double planetary gear sets, which may be configured to sum power from the engine and from the one or more components of the IVP for delivery to the transmission.

According to another aspect of the disclosure, a method is disclosed for powering a work vehicle with an engine, an IVP, an energy storage device configured to receive energy from the IVP for storage and to provide stored energy from the energy storage device to power one or more components of the infinitely variable power source, and a transmission configured to relay power from the engine and from the one or more components of the infinitely variable power source to one or more other components of the vehicle.

The transient power event may be identified, during which a present operating state of the engine of the work vehicle does not provide sufficient power for one or more operations of the work vehicle. The energy storage device may be caused to provide stored energy from the energy storage device to power the one or more components of the IVP. During the transient power event, the transmission thereby may receive power from the energy storage device via the one or more components of the IVP, such that the one or more operations of the work vehicle may be executed using, at least in part, stored energy from the energy storage device

The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features and advantages will become apparent from the description, the drawings, and the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of an example work vehicle that may include an infinitely variable transmission;

FIG. 2 is a schematic view of a power train of the vehicle of FIG. 1;

FIG. 3 is a schematic view of an infinitely variable transmission that may be included in the power train of FIG. 2;

FIG. 4 is a graphical representation of infinitely variable power source speeds and vehicle wheel speeds for various modes of operation of the infinitely variable transmission of FIG. 3;

FIG. 5 is a schematic view of another infinitely variable transmission that may be included in the power train of FIG. 2;

FIG. 6 is a graphical representation of infinitely variable power source speeds and vehicle wheel speeds for various modes of operation of the infinitely variable transmission of FIG. 5;

FIG. 7 is a schematic view of another infinitely variable transmission that may be included in the power train of FIG. 2;

FIG. 8 is a graphical representation of variable power source speeds and vehicle wheel speeds for various modes of operation of the infinitely variable transmission of FIG. 7;

FIG. 9 is a schematic view of a power train similar to that of FIG. 3, with a power storage and delivery system;

FIG. 10 is a schematic view of a power train similar to that of FIG. 7, with another power storage and delivery system; and

FIG. 11 is a diagrammatic view of a transient power event management process, which may be used with the power trains of FIGS. 9 and 10.

Like reference symbols in the various drawings indicate like elements.

DETAILED DESCRIPTION

The following describes one or more example embodiments of the disclosed power train arrangement for energy storage and delivery, as shown in the accompanying figures of the drawings described briefly above. Various modifications to the example embodiments may be contemplated by one of skill in the art.

In various known configurations, one or more planetary gear sets may be utilized to combine the power output of an IVP and an engine (e.g., an internal combustion engine). For example, in a planetary gear set a first component of the gear set (e.g., a ring gear) may receive power from the engine, a second component of the gear set (e.g., a sun gear) may receive power from the IVP, and a third component of the gear set (e.g., a planet gear carrier) may sum the power from the engine and the IVP at the output of the gear set. (For convenience of notation, “component” may be used herein, particularly in the context of a planetary gear set, to indicate an element for transmission of power, such as a sun gear, a ring gear, or a planet gear carrier.) It will be understood that such a configuration may allow for essentially infinite and continuous gear ratios for the planetary gear set. For example, for a fixed engine speed, a particular gear ratio may be set by varying the speed of the IVP with respect to the engine speed.

In certain instances, it may be useful to facilitate a powered-zero mode for a vehicle (or other machinery), in which the output speed of the vehicle wheels (or other machinery output) reaches zero speed without stopping the engine or releasing torque at the wheels. In this way, for example, vehicle power may be utilized to hold a vehicle stationary. Such a state may be obtained, for example, with a planetary gear set configured as described above. For example, if an engine is spinning a sun gear at a first positive speed and an IVP (e.g., an electric motor powered by a generator) is directed to spin a ring gear at an equivalent negative speed, an associated planet gear carrier (which may, for example, be connected to a differential drive shaft) may not spin at all. Further, if the IVP provides an output rotation at a slightly different (and opposite) speed from the engine, the vehicle may enter a “creeper” mode, in which the vehicle moves very slowly but with high wheel torque. The powered-zero and creeper modes are particularly useful for heavy-duty work vehicles, such as the tractor shown in FIG. 1, used in the agricultural, construction and forestry industries. With increasing wheel speed, the vehicle may then, eventually, enter a normal drive mode. In traditional configurations, each of these modes may be split-path modes, in which power transmission is split between a purely mechanical path from the engine and the mixed path through the IVP.

One issue relating to infinitely variable power trains may concern the relative efficiency of power transmission in various modes. It will be understood, for example, that mechanical transmission of power from an engine to a gear set (i.e., mechanical path transmission) may be a highly efficient mode of power transmission, whereas transmission of power through an IVP may be less efficient (e.g., because the mechanical power must be converted to electrical or hydraulic power by a first machine, transmitted to a second machine, and then converted back to mechanical power). Accordingly, there may exist significant motivation to utilize the mechanical path more heavily than the IVP path (e.g., by increasing the speed of the engine). However, this heavier utilization of the mechanical path may also drive up the required IVP speed for powered-zero and creeper modes, because these modes may require near or actual speed matching between the IVP and engine speeds. This may lead to increased wear on related gears and other parts (e.g., a planetary gear component receiving power from the IVP and associated bearings), even to the point of part failure. Further, to attain appropriate speeds, the size and power of a relevant IVP may need to be significantly increased from a preferred size and power. Among other advantages, the multi-mode infinitely variable transmission (“MIVT”) disclosed herein may address these issues. For example, through selective use of clutches and/or brakes, an MIVT may allow heavier utilization of a mechanical path, while avoiding the need for excessive IVP speeds in powered-zero and creeper modes.

As will become apparent from the discussion herein, an MIVT may be used advantageously in a variety of settings and with a variety of machinery. For example, referring now to FIG. 1, an MIVT may be included in the power train 22 of a vehicle 20. In FIG. 1, the vehicle 20 is depicted as a tractor. It will be understood, however, that other configurations may be possible, including configuration of vehicle 20 as a different kind of tractor, as a log skidder, as a grader, or as one of various other work vehicle types. It will further be understood that the disclosed IVT may also be used in non-work vehicles and non-vehicle applications (e.g., fixed-location power trains).

As also noted above, one advantage of the disclosed MIVT is that it may allow operation of a vehicle in a variety of powered modes (e.g., powered-zero mode, creeper mode, and split-path drive mode), which may utilize various combinations of engine and IVP power. For example, through the use of various clutches and/or brakes associated with one or more planetary gear sets, an MIVT may permit engine power to be disconnected from a IVT output, even while the engine continues to operate. For example, if an IVP drives a first component of a planetary gear set and an engine drives a second component of the planetary gear set, in certain embodiments and modes a clutch may disconnect the operating engine from the second component and a brake may stop rotation of a third component of the gear set, thereby allowing delivery of power solely from the IVP through the gear reduction of the planetary gear set. In this way, for example, only electrical power (or hydraulic power, and so on) may be utilized to drive (or hold) the vehicle 20 in certain modes, while combined electrical and engine power may be utilized to drive (or hold) the vehicle 20 in other modes. As such, among other benefits, an MIVT may avoid certain previous limitations on the fraction of power that may diverted from an engine through an electric path (or hydraulic path, and so on).

Referring now to FIG. 2, various components of an example power train 22 are depicted. For example, an engine 24 may provide mechanical power (e.g., via a rotating shaft) to an MIVT 26. The engine 24 may also provide mechanical power to an IVP 28, which may include one or more IVP machines (e.g., an electric motor and generator, or hydrostatic machine having a hydrostatic motor and associated pump). The MIVT 26 a may additionally receive mechanical power from the IVP 28.

The MIVT 26 a may include various clutches 30 and brakes 32, which may be controlled by various actuators 34. The actuators 34, in turn, may be controlled by a transmission control unit (“TCU”) 36 (or another controller), which may receive various inputs from various sensors or devices (not shown) via a CAN bus (not shown) of the vehicle 20. The MIVT 26 a may include one or more output shafts 38 a for transmission of mechanical power from the MIVT 26 a to various other components (e.g., a differential drive shaft). In certain embodiments, additional gear sets (e.g., a set of range gears) may be interposed between the MIVT 26 and other parts of the vehicle 20 (e.g., a differential drive shaft). In certain embodiments, the IVP 28 may also provide power directly to other parts of the vehicle 20 (e.g., via direct IVP drive shaft 38 b).

Referring now to FIG. 3, various internal components of an example MIVT 26 a are presented. It should be noted that the schematic representations of the transmission shown in FIG. 3 (and also the transmissions shown in FIGS. 5 and 7) illustrate example implementations in simplified form for clarity, and thus may not depict all of the components associated with the represented transmission. The engine 24 may include an internal combustion engine 24 a, which may provide mechanical power directly to a shaft S1. (As used herein, “direct” power transmission may include transmission of power by direct physical connection, integral formation, or via a simple intervening element such as an idler gear or planet gear. In contrast, for example, power transmission between a ring gear of a planetary gear set and a sun gear of the planetary gear set via a planet gear carrier (and associated planet gears) of the planetary gear set may not be considered “direct.”) An example IVP 28 a may include an electric generator 40 and an electric motor 42. The electric generator 40 may receive mechanical power via a gear 46 and a gear 44, attached to the shaft S1, and may generate electrical power for transmission to an electric motor 42. The electric motor 42 may convert the received electrical power to mechanical power and thereby rotate a shaft S2.

Although specific terms such as “generator” and “motor” may be used herein to describe various example configurations, it will be understood that these (and similar) terms may be used to refer generally to an electrical machine that may be capable of operating either as a generator or as a motor. For example, the electric generator 40 may sometimes operate as an electric motor, and the electric motor 42 may sometimes operate as a generator. Likewise, it will be understood that the actual operating modes of other infinitely variable power sources may similarly vary from those explicitly described herein.

In certain embodiments, the MIVT 26 a may include a planetary gear set 48 and a double planetary gear set 50. In certain embodiments, the planetary gear set 48 and the double planetary gear set 50 may be configured to sum mechanical power from the engine 24 a and the IVP 28 a. Through the use of one or more associated clutches and/or brakes, the MIVT 26 a may provide an output, in certain modes, that utilizes only power from IVP 28 a.

The planetary gear set 48 may include, for example, a planet gear carrier 52 holding planet gears 54, which may be meshed with a sun gear 56 and ring gear 58. Drive clutch 60 may be configured to engage planet gear carrier 52 and sun gear 56 (e.g., based upon signals from TCU 36) in order to control power transmission between these gears. For example, in a fully engaged state, drive clutch 60 may lock planet gear carrier 52 to sun gear 56. As depicted in FIG. 3, engine 24 a may directly drive planet gear carrier 52 via shaft S1. Accordingly, engagement of clutch 60 may effectively lock sun gear 56 to shaft S1 and the output of engine 24 a. Reverse brake 62 may be anchored to a fixed housing of MIVT 26 a (or another feature) and may be configured to engage to stop the rotation of ring gear 58.

In certain embodiments, an output component of the planetary gear set 48 may directly transmit power to an input component of the double planetary gear set 50. For example, the sun gear 56 may be integrally connected with the ring gear 64, thereby directly connecting an output of planetary gear set 48 (i.e., the sun gear 56) to an input to double planetary gear set 50 (i.e., the ring gear 64).

The double planetary gear set 50 may also receive power input from the IVP 28 a. For example, the electric motor 42 may drive the rotation of the shaft S2, along with an attached gear 66. The gear 66 may be meshed with a gear 68, mounted to the shaft S1, and the gear 68 may directly transmit power to (e.g., may be integrally formed with) a sun gear 70 of the double planetary gear set 50. The sun gear 70 may mesh with planet gears 72 (one shown), which may be directly connected with planet gears 74 (one shown), both sets of the planet gears 72 and 74 being carried by a planet gear carrier 76. Each of the planet gears 74 may mesh with one of various planet gears 88, which in turn may mesh with a ring gear 78. The planet gear carrier 76 may connect to the ring gear 78 (e.g., via planet gears 74 and 88), and a creeper brake 80 may be anchored to a fixed housing of the MIVT 26 a (or another feature) and configured to engage the ring 78 to stop the rotation of that component.

Planet gear carrier 76 may provide a mechanical power output from the double planetary gear set 50 for transmission of mechanical power to various parts of the vehicle 20. For example, the planet gear carrier 76 may be integrally connected with an output gear 82, which may be meshed with a gear along an idler shaft S3. In certain embodiments, an additional gear box 84 (e.g., a range gear box) may be interposed between the MIVT 26 a and other parts of the vehicle 20 (e.g., a differential drive shaft (“DDS”)) or may be included as part of the MIVT 26 a. In this way, for example, various gear shifts may be implemented over the baseline infinitely variable gear ratio provided by the MIVT 26 a.

In certain modes of operation, the MIVT 26 a (as configured in FIG. 3) may provide for powered-zero and creeper modes in which only power from the IVP 28 a is provided to the wheels of the vehicle 20. For example, the drive clutch 60 may be disengaged and the brake 80 may be engaged with the ring gear 78 (or, in certain configurations, with the ring gear 64 (not shown)). This may, accordingly, disconnect the engine 24 a from the double planetary gear set 50, while providing a fixed gear (e.g., the ring gear 78) around which the components of the double planetary gear set 50 may rotate. Mechanical power from the IVP 28 a may be provided to the sun gear 70, which may drive the planet carrier 76 around the ring gear 78. This may, in turn, cause rotation of the output gear 82, driven by the IVP 28 a but not by the engine 24 a, which may allow for the driving of the wheels of the vehicle 20 (e.g., via the gear box 84) using only power from the IVP 28 a.

In order to shift the vehicle out of this IVP-only mode, a reverse process to that described above may be executed. For example, the drive clutch 60 may be engaged, thereby connecting the engine 24 a to the sun gear 56 and the ring gear 64. At the same time (or nearly the same time), the creeper brake 80 may be disengaged, thereby allowing the double planetary gear set 50 to provide an output at the gear 82 that represents a sum of the power from the IVP 28 a and the engine 24 a. It will be understood that this selective use of two of a set of friction elements (e.g., clutches and brakes) may generally facilitate transition between various operating modes for the vehicle 20.

In certain embodiments, it may be beneficial to effect a transition between modes (e.g., between an all-IVP creeper mode and a combined drive mode) in particular ways. For example, with the drive clutch 60 engaged, it may be possible to spin the sun gear 70 (via the IVP 28 a) at a speed such that the ring gear 78 essentially stops, even without use of the brake 80. In order to provide for more seamless shifting between modes, it may be beneficial to shift between drive and creeper mode at such a point. In this way, for example, the brake 80 may be engaged and the clutch 60 may be disengaged with minimal disruption to vehicle operation. A similar seamless shift point may also be obtained for shifts from creeper to drive modes, and may represent a target point for those shift operations (and others). It will be understood, however, that in certain embodiments ramped (or other) modulation of the clutch 60 (or other components) may be utilized.

In certain applications, it may be desirable to operate the vehicle 20 in reverse, whether in creeper mode, drive mode, or otherwise. In the MIVT 26 a as depicted in FIG. 3, for example, it may be possible to engage the reverse brake 62 for this purpose.

Referring now to FIG. 4, a graph is presented of the relationship between vehicle wheel speed (in kilometers per hour) and the speed of the electric motor 42 (in revolutions per minute) for the configuration of the MIVT 26 a in FIG. 3. Various curves are presented for operation of the vehicle 20 with various range gears (not shown) engaged within the gear box 84. It will be understood that the quantities represented in FIG. 4 should be viewed as examples only.

A line 90, for example, may represent operation of the vehicle in a creeper mode (e.g., under electrical power only). It can be seen that at zero motor speed there may be zero vehicle speed, with non-zero motor speed directly proportional to vehicle speed. In creeper mode (e.g., with the brake 80 engaged, the drive clutch 60 disengaged, and an A-range gear (not shown) in the gear box 84 engaged), the vehicle 20 may accelerate to a transition point. For example, as described above, the vehicle 20 may accelerate to a point at which, based on the engine speed and relevant gear ratios, the ring 78 may be relatively stationary even without engagement of the brake 80. At this point (or another), the brake 80 may be disengaged and the clutch 60 engaged, thereby shifting the vehicle 20 into split-mode drive relatively seamlessly. The motor 42 may then begin to decelerate along a line 92, with vehicle speed (now driven in split-path mode by both the motor 42 and the engine 24 a) increasing even as the speed of the motor 42 changes direction (i.e., passes from positive rotation to negative rotation).

Continuing, the vehicle 20 may be shifted from the A-range gear in the gear box 84 to a higher B-range gear (not shown). To continue acceleration of the vehicle 20, it may now be appropriate to switch the direction of the rotation of the motor 42, thereby jumping from negative rotation and the line 92 to positive rotation and a line 94. The motor 42 may then be decelerated again, followed by a further shift to a higher C-range gear (not shown) in the gear box 84 and a corresponding jump, for the motor 42, from the line 94 to a line 96. By modulating the rotation of the motor 42 in this way, shifts between various range gears of the gear box 84 may be accomplished with the same reduction ratio at the start of the shift (e.g., at the end of A-range driving) as at the end of the shift (e.g., at the beginning of B-range driving). (It will be understood that a reduction ratio may be the product of the gear ratios of the planetary gear sets 48 and 50 and the engaged gear (e.g., the A-range gear) of the gear box 84.)

Various benefits may obtain from the configuration of FIG. 3 (and others contemplated by this disclosure). For example, in the configuration of FIG. 3 (and other configurations) the gear box 84 may be located downstream of the planetary gear sets 48 and 50. This may allow the use of the full range of torques and speeds resulting at the output of the MIVT 26 a (i.e., as may result from the various combinations of the power of the engine 24 a and the motor 42) with each range or gear of the gear box 84. For example, an electric-only mode (or any of a variety of split-path modes) may be utilized with each range or gear of the gear box 84. This may provide significant flexibility during vehicle operation.

Additionally, in the configuration of FIG. 3 (and other configurations) split-mode drive may be implemented using a relatively simple planetary path, which may decrease wear, improve life, and decrease costs for the MIVT 26 a, among other benefits. This may be particularly useful, for example, for applications in which a majority of operating time is expected to be spent in split-path mode (e.g., for various agricultural operations conducted with the vehicle 20). In split-path mode, for example, power from the engine 24 a may be provided through the clutch 60 to the ring gear 64, and power from the motor 42 being provided to the sun gear 70. These components (i.e., the ring gear 64 and the sun gear 70) may together cause rotation of the planet carrier 76 (via the planet gears 72), which in turn may cause rotation of the gear 82 and the corresponding transfer of power into the gear box 84. In contrast, in an electric-only mode, power from the motor 42 may be provided to the sun gear 70 and then, in turn, to the planet gears 72, the planet gears 74 (which may be directly connected to or integrally formed with the gears 72), and the planet gears 88. With the ring gear 78 locked by the brake 80, power may then flow from the planet gears 72, 74 and 88 to the planet carrier 76, and so on. In this way, it will be understood, fewer gear meshes may be utilized in the split-path power mode than in the electric-only mode, which may represent a relative improvement in power transfer efficiency and may also result in a relative decrease in part wear.

Referring now also to FIG. 5, another example MIVT 26 b is presented. As depicted in FIG. 5, the MIVT 26 b may include planetary gear set 98 and a double planetary gear set 100. An internal combustion engine 24 b may directly drive both a hydrostatic drive (e.g., a pump 102 and a motor 104) and a shaft S4, and the hydrostatic drive (e.g., via the motor 104) may drive a shaft S5. A planetary gear set 98 may include a sun gear 106, a planet gear carrier 108, and a ring gear 110. A drive clutch 112 may be configured to engage with the shaft S4 in order to connect the output of the engine 24 b to the sun gear 106. A creeper clutch 114 may be configured to engage both the planet gear carrier 108 and the ring gear 110, thereby potentially locking the planet gear carrier 108 and the ring gear 110 together. A reverse brake 116 may be configured to engage the ring gear 110. In certain configurations, accordingly, the reverse brake 116 may be utilized to reverse the output of the planetary gear set 98 with respect to the output of the engine 24 b.

The planetary gear set 98 may include an output that is directly connected (e.g., directly geared to or integral with) an input to the double planetary gear set 100. For example, as depicted in FIG. 5, the planet gear carrier 108 may be an output component for the planetary gear set 98 and may be directly geared (i.e., via gears 118 and 120) to a planet gear carrier 122 of the double planetary gear set 100. Further, in certain configurations, this input to the gear set 100 may rotate directly with another component of the gear set 100. For example, the planet gear carrier 122 may be formed as an integral component with a ring gear 124, such that both components rotate in unison.

The motor 104 may provide an additional input to the double planetary gear set 100. For example, via the shaft S5, the motor 104 may provide input power to both of sun gears 126 and 128. The double planetary gear set 100 may also include, for example, a ring gear 130, and a planet gear carrier 134.

In this configuration, similar to the discussion above regarding the embodiment of FIG. 3, various clutches and brakes associated with the MIVT 26 b may be utilized to switch between various operating modes for the vehicle 20. For example, when the drive clutch 112 is disengaged power may not be transmitted from the operating engine 24 b to the planetary gear set 98 or the double planetary gear set 100. Further, with the creeper clutch 114 engaged and the reverse brake 116 engaged, the gear 118 may be locked. Accordingly, engagement of the creeper clutch 114 and the reverse brake 116 may prevent rotation of both the ring gear 124 and the planet gear carrier 122 (although planet gears 132 may still rotate around the carrier 122). In this way, even though the engine 24 b may be operating, the double planetary gear set 100 may transmit to an output gear 140 only power from the motor 104 (e.g., in either a forward or a reverse creeper-mode).

In certain embodiments, additional power-transfer components may be provided to facilitate various types of vehicle operation and operational modes. For example, a low clutch 136 and a high clutch 138 may be included within the double planetary gear set 100, with the high clutch 138 configured to engage both the ring gear 130 and the output gear 140, and with the low clutch 136 configured to engage both the planet gear carrier 134 and the output gear 140. Accordingly, in creeper or other modes, the clutches 136 and 138 may be selectively activated in order to adjust the effective total gear ratio of the two planetary gear sets 98 and 100.

In certain embodiments, a gear box 142 may be interposed between the double planetary gear set 100 and other parts of the vehicle 20 (e.g., a DDS), and may include various gears (e.g., range gears). Also in certain embodiments, the configuration represented in FIG. 5 may allow transition between fixed gear ratios within the gear box 142 (and in the context of the infinitely variable gear ratio provided by the hydrostatic machines 102, 104) without necessarily changing the direction of rotation for the motor 104. For example, the vehicle 20 may start operation at zero speed, with the engine 24 b disconnected from the transmission (via the clutch 112) and with the clutch 114 and the brake 116 engaged. The motor 104, accordingly, may provide the sole power to the output gear 140 (and the gear box 142). The motor 104 may be started in the positive direction (for positive-direction creeper mode operation) or negative direction (for negative-direction creeper mode operation). Assuming, for example, an initial positive direction of travel, rotation of the motor 104 (and thereby the shaft S5) may accelerate in the positive direction, causing the sun gears 126, 128 to also accelerate. Initially, for example, the low clutch 136 may be engaged, whereby power may be transferred from the sun gear 128, via the planet gear carrier 134 to the output gear 140. Within the gear box 142, a first low range gear may be engaged, thereby completing the power transmission path from the motor 104 to other parts of the vehicle 20 (e.g., a differential drive shaft).

At a particular speed of the motor 104, depending on the particular associated gear ratios, the ring gear 110 may tend to be relatively stationary, even when the brake 116 is not engaged. As also noted above, this may provide a useful point at which to transition between operation modes (e.g., creeper mode and split-path mode) or various gears (e.g., range gears within the gear box 142). Accordingly, continuing the example above, once the motor 104 has accelerated through creeper mode to such a speed-matched point (or at various other times), the reverse brake 116 may be disengaged and the drive clutch 112 may be engaged. This may provide a mechanical transmission path for power from engine 24 b to the double planetary gear set 100. At the same time (or nearly the same time), the low clutch 136 may also be disengaged and the high clutch 138 may be engaged. However, due to the configuration represented in FIG. 5, it may not be necessary at this point to reverse the rotational direction of the motor 104 in order to continue forward acceleration of the vehicle 20 (as it may be, for example, for the configuration represented in FIG. 3). In certain embodiments, after engagement of the clutch 112 (i.e., entry into a split-path mode), the rotational speed of the motor 104 may simply be decelerated from the rotational speed at the time of the transition, with the vehicle 20 accelerating accordingly.

Referring now to FIG. 6, for example, a graph is presented of the relationship between vehicle wheel speed (in kilometers per hour) and the speed of the motor 104 (in revolutions per minute) for the configuration of the MIVT 26 b in FIG. 5. Various curves are presented for operation of the vehicle 20 with various gears (e.g., range gears) engaged within the gear box 142. It will be understood that the quantities represented in FIG. 6 should be viewed as examples only.

A line 150, for example, may represent operation of the vehicle 20 in a creeper mode (e.g., under hydrostatic power only). It can be seen that at zero motor speed there may be zero vehicle speed, with non-zero motor speed being directly proportional to vehicle speed. In creeper mode (e.g., with the reverse brake 116 and the creeper clutch 114 engaged, the drive clutch 112 disengaged, and an A-range gear (not shown) in the gear box 142 engaged), the vehicle may accelerate to a transition point. In certain embodiments, this may be a point at which, based on the engine speed and relevant gear ratios, the ring gear 110 may be relatively stationary even without engagement of the brake 116. At this transition point (or another), the brake 116 may be disengaged and the clutch 112 engaged, thereby shifting the vehicle into split-mode drive. The motor 104 may then begin to decelerate along a line 152, with vehicle speed (now driven by both the motor 104 and the engine 24 b) increasing even as the speed of the motor 104 changes direction (i.e., passes from positive rotation to negative rotation).

Continuing, the vehicle may be shifted from the former A-range gear in the gear box 142 to a higher B-range gear (not shown). To continue acceleration of the vehicle 20, it may again be appropriate to switch the direction acceleration of the rotation of the motor 104 (but not, immediately, the direction of rotation of the motor 104), and engage an appropriate range gear (with or without switching among the clutches 136 and 138). The motor 104 may then accelerate along a line 154, with the vehicle 20 accelerating accordingly.

Referring now to FIG. 7, an additional example MIVT 26 c is presented. As depicted in FIG. 7, an internal combustion engine 24 c may provide mechanical power to an electric generator 172, which may provide electrical power to an electric motor 174 via a power cable 176. The motor 174 may (e.g., via direct gearing) drive rotation of a sun gear 182 of a double planetary gear set 178. The gear set 178 may also be configured to receive mechanical power from the engine 24 c via a shaft S7, with a drive clutch 196 configured to engage both the shaft S7 and another sun gear 180. A planet gear carrier 184, including planet gears 192 may be directly connected to (e.g., integral with) a ring gear 190, which may itself be configured to receive power from the sun gear 182 via a planet gear carrier 186. A ring gear 188 may be meshed with the planet gears 192. Further, the planet gear carrier 186 may form an output component of the gear set 178 and may, for example, be directly connected to (e.g., integrally formed with) an input component of a gear box 202.

As in other embodiments discussed herein, a number of clutches and brakes within the MIVT 26 c (e.g., as represented in FIG. 7) may allow for useful transition between various operating modes, including a creeper mode powered only by the motor 174 and a split-path mode powered by both the motor 174 and the engine 24 c. For example, the clutch 196 may engage with the shaft S7 and the sun gear 180 in order to transmit power from the engine 24 c to the double planetary gear set 178. Likewise, a clutch 198 may engage both the ring gear 188 and the planet gear carrier 184 in order to lock these components together. Finally, a reverse brake 200 may engage the ring gear 188 in order to stop rotation of that gear.

In this light, it will be understood that the clutch 198, the brake 200 and the clutch 196 may be selectively engaged (and disengaged) in order to provide for various modes of operation. For example, with the clutch 196 disengaged and both the clutch 198 and the reverse brake 200 engaged, the vehicle 20 may be driven under the power only of the motor 174. Likewise, other operational modes may be possible with various other configurations (e.g., various combinations in which two of the clutch 198, the brake 200, and the clutch 196 are engaged).

Referring now also to FIG. 8, for example, a graph is presented of the relationship between vehicle wheel speed (in kilometers per hour) and the speed of the motor 174 (in revolutions per minute) for the configuration of the MIVT 26 c in FIG. 7. Various curves are presented for operation of the vehicle 20 with various gears (e.g., range gears) engaged within the gear box 202. It will be understood that the quantities represented in FIG. 8 should be viewed as examples only.

A line 212, for example, may represent operation of the vehicle 20 in a creeper mode (e.g., under electrical power only). It can be seen that at zero motor speed there may be zero vehicle speed, with non-zero motor speed relating proportionally to vehicle speed. In creeper mode (e.g., with the reverse brake 200 and the clutch 198 engaged, the drive clutch 196 disengaged, and an A-range gear (not shown) in the gear box 202 engaged), the vehicle 20 may accelerate to a transition point. For example, the vehicle 20 may accelerate to a point at which, based on the engine speed and relevant gear ratios, the ring gear 188 may be relatively stationary even without engagement of the brake 200). At this point (or another), the clutch 198 may be disengaged and the clutch 196 engaged, thereby shifting the vehicle into split-mode drive. At this time (or near this time) the motor 174 may then reverse its direction of rotation, thereby transitioning from the line 212 to a line 214. The vehicle 20, accordingly, may continue to accelerate (now driven by both the motor 174 and the engine 24 c), with vehicle speed increasing even as the speed of the motor 174 changes direction (i.e., passes from negative rotation to positive rotation). Similar shifts may also be effected, for example, into a B-range gear (not shown) from the A-range gear (not shown) by transitioning the motor 174 from the line 214 to a line 216, and so on.

In certain embodiments, including with regard to various transmission configurations discussed above, it may be useful to provide a power train arrangement with energy storage and delivery (“ESD”) capability for powering vehicle systems, in addition (or as an alternative) to a traditional engine. For example, with respect to the vehicle 20, it may be useful to provide one or more electric, hydraulic, or other energy storage devices as part of (or in communication with) the power train 22. Energy from the engine 24 may be received for storage at these devices (e.g., energy provided in mechanical form from the engine 24, then converted to non-mechanical forms for storage). The energy may then be released from storage for delivery to various vehicle components (e.g., a transmission or other power train assembly), in various beneficial ways.

In certain embodiments of the disclosed power train arrangement, an ESD system may be used to reduce the detrimental effects of transient power events for the vehicle 20. A transient power event may include events in which the power available from the engine 24 (at least under the current operating state of the engine 24) may be insufficient for one or more ongoing (or requested) operations. A transient power event may occur, for example, when a powered operation is requested by an operator, but the available (i.e., surplus) power from the engine 24 (at least at current operating conditions) is insufficient to complete the operation without detrimental effects (e.g., without reducing power supply to other vehicle systems). For example, while the engine 24 is actively powering various vehicle systems (e.g., a set of drive wheels), an operator may request an operation requiring additional power beyond that currently available from the engine 24. In certain embodiments, an ESD system may be utilized to supplement (or replace) available engine power for such an operation, while avoiding various issues (e.g., power lags, inefficient engine operation, jerking of the vehicle 20, and so on).

A transient power event may also occur, for example, when an engine is providing no power to the relevant power train. In certain embodiments, an ESD system may be utilized to provide power to various vehicle systems when an engine is in a shut off state, or is otherwise not operating.

In certain embodiments, a component of an IVP (e.g., an electric generator or hydraulic pump) may be configured to receive mechanical power from the engine 24 and convert the power to a different form (e.g., electrical power or hydraulic pressure/flow). A portion of the converted power may be routed to an energy storage device (e.g., a battery or accumulator) for storage. As needed (i.e., during a particular transient power event), stored energy may be then be released from the energy storage device to a component of the IVP (e.g., an electric motor or hydraulic motor) for conversion back to mechanical power. This mechanical power may then be routed through the vehicle 20, as needed. For example, an MIVT may be configured to receive power from the IVP, to supplement mechanical power received directly from the engine 24.

In certain implementations, an ESD system in the disclosed power train arrangements may be utilized to provide shift smoothing. During certain shift events of a transmission of the vehicle 20 (e.g., during transition from a first range or gear of a multi-stage transmission to a second range or gear of the multi-stage transmission) more power may be demanded at an input to the transmission than is available from the engine 24 (i.e., a transient power event may occur). For example, one or more clutches of the transmission may slip as the transmission begins to assume a post-shift-event load (e.g., an increased load). This slippage may result in power consumption within the transmission itself (e.g., due to the energy loss as the clutch slips), even as power is transmitted through the transmission to the transmission output. As such, the power required at the transmission input may be significantly larger than the power available at the transmission output.

As a result of this power loss (or other factors), various adverse events may occur with respect to the engine 24, the transmission, or other vehicle systems. For example, due to the excess power demand at the transmission input, the engine 24 may temporarily “droop” or suffer other reduced performance, which may be perceived by a user as a hesitation of the vehicle 20 (or of the engine 24). Similarly, the transmission may execute a sub-optimal shift, which may be perceived by a user as a jerking, stuttering, or even stalling of the vehicle 20.

Shift smoothing, as provided by an ESD system, may help to address these (and other) issues. For example, during steady (or other) operation of the vehicle 20, a portion of the power from the engine 24 may be routed to the ESD system (e.g., via an IVP) for storage (e.g., as stored electrical, hydraulic, kinetic, or other energy). During a shift event, as appropriate, the ESD system may then deliver a portion of the stored energy to the relevant transmission (e.g., via the IVP) in order to supplement the power provided directly by the engine 24. In this way, even if a shift event causes a power demand at a transmission that exceeds the (present) power output of the engine 24, power delivery from the ESD system may allow relatively smooth shifting operations. This may be useful, for example, in order to avoid the need to increase engine speed during shifting. Further, the use of an ESD system for shift smoothing may reduce the need for complex transmission designs (and controls), which might otherwise be necessary to provide smooth shifts across a variety of shift events.

An ESD system may provide various other benefits, in addition (or as an alternative) to shift smoothing. In certain embodiments, an ESD system may be utilized for load leveling, in which increases in demand for power during operations other than shift events may be met (at least in part) with stored energy from the ESD system, rather than with increased power delivery from the engine 24. In certain implementations, this may allow the engine 24 to be operated at a relatively constant load and relatively constant speed during a wide range of operations of the vehicle 20, which may in turn result in more efficient utilization of a given configuration of the engine 24. Likewise, an ESD system may be utilized to power operation of the vehicle 20 (or a sub-system thereof) without any ongoing power delivery from the engine 24. For example, in a “pure” electric (or hydraulic) mode, where the engine 24 may not be providing any power for operation of the vehicle 20, an ESD system may power operation of various vehicle systems, using previously-stored energy.

In certain embodiments, an ESD system may be included in, or may otherwise interface with, an IVP of the vehicle 20. For example, an IVP of the vehicle 20 may include a first IVP machine configured as an electric generator or hydraulic pump, which may be configured to receive mechanical power from the engine 24 and convert the power, respectively, to electrical or hydraulic (or other) form. A battery or accumulator (or other energy storage device) may be in communication with the first IVP machine such that a portion (i.e., part or all) of the converted power may be routed to the battery or accumulator for storage. A second IVP machine of the IVP (e.g., an electric motor or hydraulic motor) may be configured to receive power from the battery or accumulator (or directly from the first IVP machine), and convert the received power to mechanical form for downstream components of the vehicle power train 22.

An ESD system may be controlled in various ways. In certain embodiments, the routing of power to and from an ESD system may be regulated using a controller configured as a computing device of various designs (e.g., a processor and memory architecture, a programmable electronic circuit, and so on). In certain embodiments, for example, operation of an ESD system (as part of the disclosed power train arrangement) may be regulated by the TCU 36 or may be regulated by a different controller (not shown). An ESD system may be controlled based upon various inputs, including inputs from speed sensors (not shown) for the engine or other vehicle components, inputs from sensors (not shown) relating to shift operations, vehicle power consumption or demand, or inputs from various other devices (not shown).

Referring also to FIG. 9, an example power train arrangement including an ESD system is depicted. The power train of FIG. 9 is configured to transmit mechanical power from an internal combustion engine 24 d to various vehicle components and systems. As depicted, mechanical power from the engine 24 d is routed along a shaft S8 to a planetary gear set 48 d and a double planetary gear set 50 d, as well as to an electric generator 230. (It will be understood that, in other configurations, a different IVP machine may be utilized in place of, or in addition to, the generator 230.) The generator 230 is in electrical communication with a battery 234 (or other storage device for electric energy) and with an electric motor 232. Collectively, the generator 230 and motor 232 may be viewed as an IVP 28 d, in communication with an ESD system 228 that includes the battery 234 (or batteries 234, as appropriate) as well as various other components (not shown), including various power electronics, controllers, and so on.

The planetary gear set 48 d and double planetary gear set 50 d, as well as the IVP 28 d, is configured to operate in a similar fashion to the planetary gear set 48, double planetary gear set 50, and IVP 28 a of FIG. 3 (as discussed in detail above), in order to provide an MIVT 26 d with similar functionality to the MIVT 26 a. The MIVT 26 d may exhibit various differences, however. For example, in FIG. 9, it can be seen that a shaft S16 is configured to receive power from the shaft S8 via the drive gear for the generator 230, in order to power rotation of an auxiliary drive pulley 250. Likewise, a shaft S10 powered by a gear 44 d of the shaft S8 (which also provides power to the generator 230) may provide power to transmission control, scavenge, and other pumps.

During operation, power from the engine 24 d may be routed in various ways through the MIVT 26 d to a gear box 84 d (e.g., configured as a controllable gear box), in order to provide infinitely variable, multi-mode power transmission to various vehicle systems. As depicted, for example, an output gear 82 d of the double planetary gear set 50 d is configured to mesh with input gears 236 and 238 of the gear box 84 d. Through the selective operation of clutches 252, the output gear 82 d may accordingly power rotation of one of the transmission shafts S11 and S13, respectively. Selective control of various other clutches 254 may be utilized to shift the gear box 84 d among various range gears 240, 242, 244, 246 and 248, which may correspond, respectively, to ranges A through E for the gear box 84 d. In this way, power may be routed from the engine 24, as well as from the motor 232, to the differential drive shaft S12 a. Also as depicted, a brake 256 and clutch 258 may be controlled to transmit power from the gear box 84 d to a drive shaft S12 b for mechanical front wheel drive. (It will be understood that the depicted configuration of the various gears of the gear box 84 d is presented as an example only. An ESD system may also be utilized with regard to other configurations of the gear box 84 d).

Other devices and functionality may also be provided. For example, it can be seen that the gear 44 d of the shaft S8 is configured to rotate an idler gear 68 d on the shaft S12 a, as well as to provide power to the generator 230. In turn, the gear 68 d may power rotation of a PTO shaft S14 and, in certain configurations, a front PTO shaft S15.

As regulated by an appropriate controller (not shown), a portion of the power received at the generator 230 may be routed, once converted to electrical form, to the ESD 228 for storage in the battery 234. In certain implementations, power may be routed from the generator 230 to the battery 234 continuously, as long as the engine 24 d is running and the battery 234 is not fully charged. In certain implementations, power may be routed from the generator 230 to the battery 234 more selectively. For example, under certain control strategies, power may be routed from the generator 230 to the battery 234 only when it has been detected (e.g., via various engine or other sensors (not shown)) that the engine 24 d is producing surplus power with regard to the current power demands of vehicle operation.

As needed, energy may be released from the battery 234 to power operation of the motor 232. As described above, with regard to motor 42 of FIG. 3, power from the motor 232 may then be routed through the double planetary gear set 50 d in order to supplement (or replace) power from the engine 24 d. This may be useful, for example, in order to ensure that appropriate power is provided to the various systems and devices of the vehicle 20, even while the engine 24 d is maintained at an optimal, and relatively constant operating speed.

In certain implementations, power from the battery 234 may be utilized, via the motor 232, for shift smoothing operations. For example, during (or before or after) a shift from the A-range gear 240 to the B-range gear 242, a relevant controller may identify that additional power may be required at the gear box 84 d in order to ensure a smooth shift and, in certain embodiments, to avoid the need to increase engine speed or power. Accordingly, for the A-to-B shift event (and other shift events), energy may be released from the battery 234 to the motor 232, such that the motor 232 may provide additional power to the gear box 84 d (i.e., via the double planetary gear set 50 d).

Shift smoothing, such as in the example described above, may be implemented based upon a variety of factors. In certain implementations, for example, a signal from the TCU 36 (or other device) may indicate that a shift between gears of the gear box 84 d is about to occur (or is occurring or has recently occurred). Where such a shift event is identified as (or expected to) result in a transient power event, power may be routed from the ESD 228 accordingly. In certain implementations, engine sensors, shaft speed sensors, or other sensors (not shown) may detect indications of a power deficiency at the gear box 84 d (e.g., due to clutch slippage within the gear box 84 d during a shifting operation). Routing of power from the ESD 228 to the gear box 84 d may then be implemented accordingly.

In certain implementations, power from the battery 234 may be utilized for other operations. For example, where operation of the engine 24 d may not be possible or practical (e.g., during operation of the vehicle 20 within an enclosed space), energy from the battery 234 may be utilized to implement electric-only operation of the vehicle 20. In certain implementations, electric-only operation may be implemented automatically (e.g., based upon receiving a drive or other command when the vehicle is keyed on, but the engine 24 d is off). In certain implementations, electric-only operation may be implemented based upon other factors (e.g., based upon an operator toggling a particular switch, button, or lever).

As another example, where use of a particular vehicle tool imposes increased power demands on the vehicle 20, energy from the battery 234 may be utilized to ensure that appropriate power is available at the tool, without significantly adverse effect on the operation of other vehicle systems (e.g., the vehicle drive wheels) or a significant increase in engine speed. For example, where a mechanical tool (e.g., a baling device, seeding device, soil-conditioning device, cutting blade, and so on) is being driven by the PTO shaft S14, or a hydraulic tool (e.g., a loading bucket, dump truck bed, excavator arm, soil-conditioning device, and so on) is being operated using power from the front PTO shaft S15 or another shaft (i.e., as converted by an appropriate hydraulic pump (not shown)), the drive train of the vehicle 20 may be subjected to increased power demands. In certain embodiments, accordingly, during operation of such a tool, energy from the battery 234, as converted to mechanical energy by the motor 232, may be utilized to supplement (or replace) power from the engine 24 d with respect to the relevant tool (or other vehicle systems).

In certain implementations, power from the battery 234 may be utilized automatically, whenever any vehicle tool (or any vehicle tool of particular configuration) is operated. In certain implementations, power from the battery 234 may be utilized more selectively. For example, engine sensors, shaft speed sensors, or other sensors (not shown) may detect indications of a power deficiency due to tool operation, and power may be drawn from the battery 234 appropriately.

Referring also to FIG. 10, another example MIVT 26 e is configured similarly to the MIVT 26 c of FIG. 7. An internal combustion engine 24 e provides mechanical power via a shaft S17 to a double planetary gear set 178 e as well as to an electric generator 172 e (or other IVP machine) included in an IVP 28 e. The generator 172 e converts the mechanical power from the engine 24 e to electrical power, which is routed to an electric motor 174 e. The motor 174 e then converts the electrical power to mechanical power, which is also routed to the double planetary gear set 178 e. In this way, the MIVT 26 e, via the double planetary gear set 178 e, may be utilized to combine power from the engine 24 e and the IVP 28 e, in order to provide continuously variable power to a transmission 202 e.

In the embodiment depicted, the generator 172 e is in electrical communication with a battery 260 (or other storage device for electric energy), as well as with the motor 174 e. In this way, mechanical energy from the engine 24 e may be stored as electrical energy in the battery 260, and released, as appropriate, via the motor 174 e, to provide power to the double planetary gear set 178 e. As described in detail with respect to the configuration of FIG. 9, energy from the battery 260 may be utilized to provide shift smoothing, to operate the vehicle 20 in an electric-only mode, to power operation of a tool of the vehicle 20 (or to power other vehicle systems during operation of such a tool), and so on.

It will be understood that the various storage devices of an ESD system (e.g., the batteries 234 and 260) may receive and store energy from sources other than the relevant engine (e.g., the engines 24 d and 24 e). For example, in certain implementations, regenerative systems (e.g., systems for capturing energy from braking operations) may be configured to route power to an ESD system for later use (e.g., for shift smoothing, electric-only operation, and so on) or may form part of an ESD system. Likewise, it will be understood that an ESD system may be utilized with power trains and transmissions (including MIVTs) other than those specifically depicted. In certain embodiments, for example, an ESD system (not shown) may be implemented with respect to the power train depicted in FIG. 5 via a hydraulic accumulator 264 (see FIG. 5, hydraulic connections not shown), or with respect to various other power train configurations (not shown).

Various of the operations described above (and others) may be implemented as part of a transient power event management (“TPEM”) method. Referring also to FIG. 11, for example, a TPEM method 300 may be implemented for the vehicle 20 by various controllers (e.g., the TCU 36) or other devices.

The TPEM method 300 may include identifying 302 a transient power event. For example, by way of an engine speed sensor, various shaft speed sensors, other sensors or devices, a controller may identify 302 that a current (or imminent) operating state of the relevant vehicle has resulted (or is likely to result) in a power deficiency. For example, a shift operation 304 (e.g., a, recent, ongoing, or imminent shift operation 304) may be identified 302, during which a transmission may demand more power from an engine (e.g., due to clutch slippage) than may be available from the engine (at least in the current operating state). For example, due to clutch slippage during a shift event, more power may be demanded from the engine at the input to a transmission than is available from the engine at the current engine speed. Similarly, operation 306 of a tool (e.g., an ongoing or imminent operation 306 of the tool) may be identified 302, during which the power requirements of the tool (e.g., in combination with other power requirements for other vehicle systems) may exceed the available power from the engine. In certain implementations, identifying 302 a transient power invent may include identifying 302 the operation of the vehicle (or a subsystem thereof) while the engine is in a shut off (or otherwise un-powered) state 308. For example, a drive operation or the operation of a vehicle tool (e.g., an ongoing or imminent drive or tool operation) may be identified 302 while the engine is in a shut off state 308.

The method 300 may further include causing 320 an energy storage device (e.g., as may form part of a larger ESD system) to provide stored energy to a component of an IVP (e.g., an IVP machine). For example, the method 300 may be utilized to cause 320 energy from a battery to be provided to an electric motor, to cause 320 energy from a hydraulic accumulator to be provided to a hydraulic motor, and so on. (In certain implementations, it will be understood that this may be preceded by the method 300 causing 322 energy to be stored in the IVP. In certain implementations, energy may be stored in the IVP in other ways.)

The method 300 may then include providing 330 power from the component of the IVP (e.g., from an IVP machine) to a transmission. For example, the method 300 may include providing 330 power from an electric or hydraulic motor to an MIVT of various configurations, to a transmission with fixed gear ratios, or to other transmissions included in the relevant power train.

In certain implementations, the method 300 may further include providing 340 power to the transmission from the engine. For example, where the engine is not in a shut-off state 308, an MIVT (or other device) may be utilized to sum the power received, respectively, from the engine and from the IVP, such that power from both the engine and the IVP may be provided 330, 340 to the relevant transmission.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that any use of the terms “comprises” and/or “comprising” in this specification specifies the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.

The description of the present disclosure has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the disclosure in the form disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the disclosure. Explicitly referenced embodiments herein were chosen and described in order to best explain the principles of the disclosure and their practical application, and to enable others of ordinary skill in the art to understand the disclosure and recognize many alternatives, modifications, and variations on the described example(s). Accordingly, various other implementations are within the scope of the following claims. 

What is claimed is:
 1. A power train arrangement for a work vehicle with an engine, the power train arrangement comprising: an infinitely variable power source; an energy storage device configured to receive energy from the infinitely variable power source for storage and to provide stored energy from the energy storage device to power one or more components of the infinitely variable power source; and a transmission configured to relay power from the engine and from the one or more components of the infinitely variable power source to one or more other components of the vehicle; a controller configured to: identify a transient power event, during which the engine, while operating in a present operating state, provides insufficient power for one or more operations of the work vehicle; and based upon identifying the transient power event, cause the energy storage device to provide stored energy from the energy storage device to power the one or more components of the infinitely variable power source; wherein, during the transient power event, the transmission receives power from the energy storage device via the one or more components of the infinitely variable power source, such that the one or more operations of the work vehicle are executed using, at least in part, stored energy from the energy storage device; and an infinitely variable transmission including: a double planetary gear set having a first input component, a second input component, and an output component, and including a first clutch, a second clutch, and a brake; wherein the first input component is configured to receive a first mechanical power input for the double planetary gear set from the engine; wherein the first clutch is configured to engage the first input component in order to control mechanical power transmission between the first input component and the engine; wherein the second input component receives a second mechanical power input for the double planetary gear set from the one or more components of the infinitely variable power source; and wherein the double planetary gear set is configured to sum mechanical power from the engine and the one or more components of the infinitely variable power source and provide the summed power to the output component, the output component providing the summed power directly to the transmission, the transmission thereby receiving power from the energy storage device, during the transient power event, via the output component.
 2. The power train arrangement of claim 1, wherein, during the transient power event, the transmission also receives mechanical power from the engine, such that the one or more operations of the work vehicle are executed using, at least in part, mechanical power from the engine and stored energy from the energy storage device.
 3. The power train arrangement of claim 1, wherein the transient power event includes a shift operation; and wherein, during the shift operation, a power requirement at the transmission for execution of the one or more operations of the work vehicle exceeds the power provided by the engine in the present operating state.
 4. The power train arrangement of claim 1, wherein the transient power event includes operation of a tool of the work vehicle; and wherein a power requirement for operation of the tool exceeds the power available from the engine for operation of the tool, in the present operating state of the engine.
 5. The power train arrangement of claim 1, wherein, in the present operating state, the engine is shut off, such that during the transient power event no power is provided to the work vehicle by the engine.
 6. The power train arrangement of claim 1, wherein the infinitely variable power source includes one or more of a pair of electric machines and a pair of hydraulic machines; and wherein the energy storage device includes, respectively, one or more of an electrical storage device and a hydraulic storage device.
 7. The power train arrangement of claim 1, wherein the first input component includes a first sun gear and the second input component includes a second sun gear; and wherein a first ring gear of the double planetary gear set is integral with a first planet gear carrier supporting one or more first planet gears meshed with both the first sun gear and a second ring gear of the double planetary gear set; and wherein, the output component includes a second planet gear carrier supporting one or more second planet gears meshed with both the second sun gear and the first ring gear of the double planetary gear set.
 8. The power train arrangement of claim 7, wherein the second clutch is configured to engage one or more of the second ring gear and the first planet gear carrier in order to control relative motion of the second ring gear and the first planet gear carrier; and wherein the brake is configured to engage the second ring gear in order to stop rotation of the second ring gear.
 9. A method for powering a work vehicle, wherein the work vehicle includes an engine, an infinitely variable power source, an energy storage device configured to receive energy from the infinitely variable power source for storage and to provide stored energy from the energy storage device to power one or more components of the infinitely variable power source, and a transmission configured to relay power from the engine and from the one or more components of the infinitely variable power source to one or more other components of the vehicle, the method comprising: identifying a transient power event, during which the engine, operating in a present operating state, provides insufficient power for one or more operations of the work vehicle; and based upon identifying the transient power event, causing the energy storage device to provide stored energy from the energy storage device to power the one or more components of the infinitely variable power source; wherein, during the transient power event, the transmission receives power from the energy storage device via the one or more components of the infinitely variable power source, such that the one or more operations of the work vehicle are executed using, at least in part, stored energy from the energy storage device; wherein the vehicle further includes an infinitely variable transmission, including a double planetary gear set having a first input component, a second input component, and an output component, and including a first clutch, a second clutch, and a brake; wherein the first input component is configured to receive a first mechanical power input for the double planetary gear set from the engine; wherein the first clutch is configured to engage the first input component in order to control mechanical power transmission between the first input component and the engine; wherein the second input component receives a second mechanical power input for the double planetary gear set from the one or more components of the infinitely variable power source; and wherein the double planetary gear set is configured to sum mechanical power from the engine and the one or more components of the infinitely variable power source and provide the summed power to the output component, the output component providing the summed power directly to the transmission, the transmission thereby receiving power from the energy storage device, during the transient power event, via the output component.
 10. The method of claim 9, wherein, during the transient power event, the transmission also receives mechanical power from the engine, such that the one or more operations of the work vehicle are executed using, at least in part, mechanical power from the engine and stored energy from the energy storage device.
 11. The method of claim 9, wherein the transient power event includes a shift operation; and wherein, during the shift operation, a power requirement at the transmission for execution of the one or more operations of the work vehicle exceeds the power provided by the engine in the present operating state.
 12. The method of claim 9, wherein the transient power event includes operation of a tool of the work vehicle; and wherein a power requirement for operation of the tool exceeds the power available from the engine for operation of the tool, in the present operating state of the engine.
 13. The method of claim 9, wherein, in the present operating state, the engine is shut off, such that during the transient power event no power is provided to the work vehicle by the engine. 